Grease thickened with ureido compound and alkaline earth metal aliphatic carboxylate

ABSTRACT

1. A GREASE COMPOSITION COMPRISING A MAJOR PART OF A LUBRICATING OIL CONTAINING (1) FROM 0.5 TO 10 WEIGHT PERCENT OF A MON OR POLYUREA COMPOUND OR MIXTURE OF MONO OR POLYUREA COMPOUNDS HAVING FROM 1 TO 8 UREIDO GROUPS AND HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 375 AND 2,500 AND (2) FROM 3 YO 30 WEIGHT PERCENT OF AN ALKALINE EARTH METAL ALIPHATIC MONOCARBOXYLATE HAVING FROM 1 TO 3 CARBONS, WHEREIN THE WEIGHT RATIO OF ALKALINE EARTH METAL CARBOXYLATE TO MONO AND POLYUREA COMPOUNDS IS FROM 1 TO 15.

Patented Nov. 5, 1974 U.S. Cl. 252-18 19 Claims ABSTRACT OF THEDISCLOSURE A novel grease composition is prepared by admixing alubricating oil with 0.5 to weight percent of a mono or polyureacompound having from 1 to 8 ureido groups and having a molecular weightbetween about 375 to 2500 and from 3 to 30 weight percent of an alkalineearth metal aliphatic monocarboxylate having from 1 to 3 carbon atomsand wherein the weight ratio of alkaline earth metal carboxylate to monoand polyurea compounds is from 1 to 15.

This invention relates to a new grease composition. More particularly,this invention relates to an improved grease lubricant containing apolyurea thickening agent.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part ofapplication Ser. No. 244,864, filed Apr. 17, 1972, now abandoned.

BACKGROUND OF THE INVENTION Modern technology is currently supplying thegeneral public and the process industries with machinery which isdesigned to operate under a wider range of temperatures and undergreater loads than previously available. In addition, many of the newermachines are designed to operate at extremely high speeds. Many of thesemachines require certain specific lubricating properties which are notavailable in the conventional lubricants. Thus, modernization of highspeed and high temperature equipment has strained the petroleum industryfor the development of a second generation of lubricants capable ofsatisfying the requirements of the new machines. Recently, for example,there has been an increased demand for lubricants capable of performingwell at temperatures above 300 F. in high speed bearings and gears forperiods in excess of 500 hours. In addition, with the furtherdevelopment of the high speed sealed bearings, the lubricant must beable to endure for the life of the bearing.

There have been numerous grease compositions developed which satisfymost of the new more stringent requirements. Many of these compositions,however, are entirely too expensive for commercialization or only meetsome of the lubricating requirements and fail in others. One type oflubricant currently available is the ubiquitous lithium greases. Thesegreases are simply a mixture of a hydrocarbon base oil and lithiumhydroxy stearate with minor amounts of other additives. Although thesegreases exhibit good lubricating properties and perform well at moderatetemperatures, their application in high temperature and high speedmachinery has not been entirely successful. The lithium greases tend todeteriorate in these machines at high temperatures, particularly attemperatures above 350 F. The deterioration leads to a rapid loss oflubrication and ultimately failure of the equipment.

Another type of grease composition which has excellent lubricatingproperties at the higher temperatures is comprised of a lubricating oil(natural or synthetic) containing a polyurea additive. This type oflubricant is disclosed in U.S. Pat. Nos. 3,242,210; 3,243,372;3,346,497; and 3,401,027, all assigned to the Chevron Research Company.The polyurea component imparts a significant high temperature stabilityto the grease and, in fact, effectsa mild anti-thixotropic property,i.e., increases in viscosity with increasing shear, to the lubricant.This property of the lubricant is advantageous to prevent thesegregation or loss of grease from the moving parts of the machine.While this grease has solved most of the problems associated with theolder lubricants, it is handicapped by the requirement of relativelylarge amounts of polyurea (between 8 and 20 weight percent) and itsrelatively high costs. In addition, the polyurea component does notimpart extreme pressure properties to the lubricant and, accordingly, EPadditives must be added in applications involving high contactpressures. A need therefore exists for a grease composition which can beused in high temperature and high speed applications, that exhibits goodstability over prolonged periods, that exhibits both extreme pressureand antiwear properties, and that is relatively inexpensive to produce.

It is, therefore, an object of this invention to provide a new improvedgrease composition.

It is another object of this invention to provide an improved greasecomposition capable of performing well at high temperatures forprolonged periods.

It is another object of this invention to provide a relativelyinexpensive grease composition capable of performing well at hightemperatures in high speed application and which exhibits good EPproperties.

It is another object of this invention to provide a method of making animproved grease composition.

SUMMARY OF THE INVENTION The aforegoing objects and their attendantadvantages can be realized by a composition comprising a major part of alubricating oil containing (1) from 0.5 to 10 weight percent of a monoor polyurea compound or mixture of mono or polyurea compounds havingfrom 1 to 8 ureido groups and having a molecular weight between about375 and 2,500 and (2) from 3 to 30 weight percent of an alkaline earthmetal aliphatic monocarboxylate having from 1 to 3 carbon atoms, whereinthe weight ratio of alkaline earth metal carboxylate to mono andpolyurea compounds is from 1 to 15.

By incorporating an alkaline earth metal carboxylate within the greasecomposition, we have found that the mono or polyurea content may bereduced by 50 percent of that required in the prior mono or polyurealubricants for the same dropping point and other physical properties.Moreover, the presence of the metal carboxylate imparts good extremepressure properties to the lubricant and thus the addition of other EPadditives is not necessary in many applications.

The exact mechanism of the mono or polyurea compound and the metalcarboxylate in effecting the improved lubricating properties is unknown.However, without being bound by the theory, it is believed that themetal carboxylate complexes in some manner with the mono or polyureacompound to elfect a combined thickening action. Although the mechanismis unknown, it is known that a synergism exists between the twocomponents such that the lubricating properties of the grease aresubstantially improved over either the mono or polyurea or metalcarboxylate employed alone. For example, the combination effects aremarkable increase in the antiwear properties of the grease.

Polyurea Component The mono or polyurea component of this invention is awater and oil insoluble organic compound having a molecular weightbetweenabout 375 and 2,500 and having at least one ureido group andpreferably between about 2 and 6 ureido groups. A ureido group asreferred to herein is defined as I. A diisocyanate having the formula:OCNR-NCO wherein R is a hydrocarbylene having from 2 to 30 carbons andpreferably from 6 to 15 carbons and more preferably 7 carbons.

II. A polyamine having a total of 2 to 40 carbons and having theformula:

Bo Bo Bo H il IR1 l IR2I I- N N\E X y L wherein R and R are the same ordifferent type of hydro carbylenes having from 1 to 30 carbons andpreferably from 2 to 10 carbons and more preferably from 2 to 4 carbons;R is selected from hydrogen or a C C, alkyl and preferably hydrogen; xis an integer from 0 to 2; y is 0 or 1 and z is an integer equal 0 wheny is 1 and equal to 1 when y is 0.

III. A monofunctional compound selected from the group consisting ofmonoisocyanate having 1 to 30 carbons, preferably from to 24 carbons, amonoamine having from 1 to 30 carbons preferably from 10 to 24 carbons,and mixtures thereof.

The reaction can be conducted by contacting the three reactants in asuitable reaction vessel at a temperature between about 60 to 320 F.,preferably from 100 to 300 F. for a period from 0.5 to 5 hours andpreferably from 1 to 3 hours. The molar ratio of the reactants presentusually varies from 0.1-2 moles of monoamine or monoisocyanate and 0-2moles of polyamine for each mole of diisocyanate. When the monoamine isemployed, the molar quantities are preefrably (n+1) moles ofdiisocyanate, (n) moles of diamine and 2 moles of monoamine. When themonoisocyanate is employed, the molar quantities are preferably (n)moles of diisocyanate, (n+1) moles of diamine and 2 moles ofmonoisocyanate.

A particularly preferred class of mono or polyurea compounds hasstructures defined by the following general formulae:

4 wherein:

n is an integer from 0 to 3;

R is the same or different hydrocarbyl having from 1 to 30 carbon atoms,preferably from 10 to 24 carbons;

R is the same or different hydrocarbylene having from 2 to 30 carbonatoms, preferably from 6 to 15 carbons; and

R is the same or different hydrocarbylene having from 1 to 30 carbonatoms, preferably from 2 to 10 carbons.

As referred to herein, hydrocarbyl is a monovalent organic radicalcomposed of hydrogen and carbon and may be aliphatic, aromatic oralicyclic or combinations thereof, e.g., aralkyl, alkyl, aryl,cycloalkyl, alkylcycloalkyl, etc., and may be saturated or olefinicallyunsaturated (one or more double bonded carbons, conjugated ornonconjugated). The hydrocarbylene, as defined in R and R above, is adivalent hydrocarbon radical which may be aliphatic, alicyclic, aromaticor combinations thereof, e.g., alkylarylene, aralkylene,alkylcycloalkylene, cycloalkylarylene, etc., having its two freevalences on different carbonatoms.

The mono or polyureas having the structure presented in Formula 1 aboveare prepared by reacting (n+1) moles of diisocyanate with two moles of amonoamine and (n) moles of a diamine. (When n equals zero in the aboveFormula 1, the diamine is deleted.) Mono or polyureas having thestructure presented in Formula 2 above are prepared by reacting (n)moles of a diisocyanate with (n+1) moles of a diamine and two moles of amonoisocyanate. (When n equals zero in the above Formula 2, thediisocyanate is deleted.) Mono or polyureas having the structurepresented in Formula 3 above are prepared by reacting (11) moles of adiisocyanate with (11) moles of a diamine and one mole of amonoisocyanate and one mole of a monoamine. (When n equals zero inFormula 3, both the diisocyanate and diamine are deleted.)

In preparing the above mono or polyureas, the desired reactants(diisocyanate, monoisocyanate, diamine and monoamine) are admixed withina suitable reaction vessel in the proper proportions. The reaction mayproceed without the presence of a catalyst and is initiated by merelycontacting the component reactants under conditions conducive for thereaction. Typical reaction temperatures range from 20 C. to C. underatmospheric pressure. The reaction itself is exothermic and,accordingly, by initiating the reaction at room temperature, elevatedtemperatures are obtained. However, external heating or cooling may bedesirable.

Reactants The monoamine or monoisocyanate used in the formulation of themono or polyurea will form the terminal end groups. These terminal endgroups will have from 1 to 30 carbon atoms, but are preferably from 5 to28 carbon, and more desirably from 6 to 25 carbon atoms.

Illustrative of various monoamines are pentylamine, hexylamine,heptylamine, octylamine, decylamine, dodecylamine, tetradecylamine,hexadecylamine, octadecylamine, eicosylamine, dodecenylamine,hexadecenylamine, octadecenylamine, octadecadienylamine, abietylamine,aniline, toluidene, naphthylamine, cumylamine, bornylamine,fenchylamine, tertiary butyl aniline, benzylamine, beta-phenethylamine,etc. Particularly preferred amines are prepared from natural fats andoils or fatty acids obtained therefrom. These starting materials can bereacted with ammonia to give first amides and then nitriles. Thenitriles are then reduced to amines, conveniently by catalytichydrogenation. Exemplary amines prepared by the method includestearylamine, laurylamine, palmitylamine, oleylarnine,petroselinylamine, linoleylamine, linolenylamine, eleostearylamine, etc.The unsaturated amines are particularly preferred.

Illustrative of monoisocyanates are hexylisocyanate, decylisocyanate,dodecylisocyanate, tetradecylisocyanate, hexadecylisocyanate,phenylisocyanate, cyclohexylisocyanate, xyleneisocyanate,cumeneisocyanate, abietylisocyanate, cyclooctylisocyanate, etc.

The polyamines, which form the internal hydrocarbon bridges between theureido groups usually contain from 2 to 40 carbons and preferably from 2to 30 carbon atoms, more preferably from 2 to 20 carbon atoms. Exemplarypolyamines include diamines such as ethylenediamine, propanediamine,butanediamine, hexanediamine, dodecanediamine, octanediamine,hexadecanediamine, cyclohexanediamine, cyclooctanediamine,phenylenediamine, tolylenediamine, xylylenediamine, dianiline methane,ditoluidinemethane, bis(aniline), bis(toluidine), piperazine, etc.,triamines, such as aminoethyl piperazine, diethylene triamine,dipropylene triamine, N methyl diethylene triamine, etc., and higherpolyamines such as triethylene tetramine, tetraethylene pentamine,pentaethylene hexa mine, etc.

Representative examples of diisocyanates include hexanediisocyanate,decanediisocyanate, octadecanediisocyanate, phenylenediisocyante,tolylenediisocyanate, bis(diphenylisocyanate), methylenebis(phenylisocyanate), etc.

Another preferred class of mono-polyurea compounds which may besuccessfully employed in the practice of this invention include thefollowing:

wherein:

n is an integer of 1 to 3, R is defined supra; X and Y are monovalentradicals selected from Table I below.

In the Table, R is defined supra, R is the same as R; and defined supra,R is selected from the group consisting of arylene radicals of 6 to 16carbon atoms and alkylene groups of 2 to 30 carbon atoms, and R isselected from the group consisting of alkyl radicals of having from 10to 30 carbon atoms and aryl radicals having from 6 to 16 carbon atoms.

Mono or polyurea compounds described by the above formula (4) can bedescribed as amides and imides of mono, di, and tri ureas. Thesematerials are formed by reacting in the selected proportions of suitablecarboxylic acids or internal carboxylic anhydrides, with a diisocyanateand a polyamine with or without a monoamine or monoisocyanate. The monoor polyurea compounds are prepared by blending the several reactantstogether in a suitable reaction vessel and heating them to a temperatureranging from 70 F. to 400 F. for a period sufficient to cause formationof the compound, generally from 5 minutes to 1 hour. The reactants canbe added all at once or sequentially.

Suitable carboxylic acids include aliphatic carboxylic acids of about 11to 31 carbon atoms and aromatic carboxylic acid of 7 to 17 carbon atoms.Examples of suitable acids include aliphatic acids such as lauric,myristic, palmitic, margaric, stearic, arachidic, behenic, lignocericacid, etc.; and aromatic acid such as benzoic acid, l-naphthoic acid,Z-naphthoic acid, phenylacetic acid, hydrocinnamic acid, cinnamic acid,mendelic acid, etc. Suitable anhydrides which may be employed are thosederived from dibasic acids which form a cyclic anhydride structure, forexample, succinic anhydric, maleic anhydride, phthalic anhydride, etc.Substituted anhydrides, such as alkenyl succinic anhydride of up to 30carbon atoms are further examples of suitable materials.

Examples of suitable diisocyanates, monoisocyanates, monoamines andpolyamines are described supra.

The mono or polyurea compounds are generally mixtures of compoundshaving structures wherein n varies from 0 to 4, or n varies from 1 to 3,existent within the grease composition at the same time. For example,when a monoamine, a diisocyanate and a diamine are concurrently presentwithin the reaction zone, as in the preparation of mono or polyureashaving the structure shown in Formula 2, some of the monoamine may reactwith both sides of the diisocyanate to form a diurea. In addition to theformulation of diurea, simultaneous reactions can be occurring to formthe tri, tetra, penta, hexa, octa, etc., ureas. Particularly goodresults have been realized when the polyurea compound has an average offour ureido groups.

The amount of mono or polyurea compound in the final grease compositionwill be sufiicient to thicken the base oil to the consistency of greasewhen combined with the alkaline earth metal carboxylate. Generally, theamount of mono or polyurea will range from 1 to 15 weight percent andpreferably from 2 to 7 weight percent of the final grease composition.

In instances where an oil concentrate is desired, the concentration ofthe mono or polyurea compound in the base oil or an oleaginous organicliquid can vary between about 10 and 30 weight percent of the finalconcentrate. The employment of concentrates provides a convenient methodof handling and transporting the mono or polyurea compounds forsubsequent dilution and use.

Alkaline Earth Metal Aliphatic Monocarboxylate The second component ofthe grease composition is an alkaline earth metal aliphaticmonocarboxylate having from 1 to 3 carbon atoms. Any of the alkalineearth metals can be employed herein, e.g., magnesium, calcium,strontium, barium, etc. However, calcium is the most preferred. Thecarboxylate group preferably has from 1 to 3 carbon atoms and morepreferably 2 carbon atoms. Exemplary compounds which may be successfullyemployed herein include calcium formate, barium formate, magnesiumformate, magnesium acetate, calcium acetate, strontium acetate, bariumacetate, calcium propionate, barium propionate, magnesium propionate,etc.

The amount of alkaline earth metal carboxylate present within the greasecomposition may vary depending upon the lubricating property desired,the particular mono or polyurea constituent selected, the type ofalkaline earth metal carboxylate selected, etc. However, generally themetal carboxylate will range from 3 to 30 weight percent of the finalgrease composition and preferably between about 4 and 15 weight percent.The ratio of alkaline earth metal carboxylate to the mono or polyureaconstituent will also vary depending upon the aforementioned conditions,but will generally range on a Weight basis from 1 to 15 parts of metalcarboxylate per part of mono and polyurea and preferably from 3 to 7parts per part of mono and polyurea.

A concentrate of the mono or polyurea compound and metal carboxylate mayalso be formulated. The concentration of the metal carboxylate can varyfrom 20 to 50 weight percent and preferably from 25 to 40 weight percentof the concentrate. The base oil is the preferred liquid medium of theconcentrate since it can be readily diluted to form the desired greasecomposition.

Base Oil The third component which must necessarily be present in thecomposition of this invention is a liquid base oil. The base oils whichmay be employed herein include a wide variety of lubricating oils suchas naphthenic-base, parafiin-base, and mixed-base lubricating oils.Other hydrocarbon oils include lubricating oils derived from ,coalproducts and synthetic oils, e.g., alkylene polymers (such as, polymersof propylene, butylene, etc., and mixtures thereof), alkylene oxide-typepolymers (e.g., alkylene oxide polymers prepared by polymerizingalkylene oxide, e.g., propylene oxide polymers, etc., in the presence ofwater or alcohols, e.g., ethyl alcohol), carboxylic acid esters (e.g.,those which were prepared by esterifying such carboxylic acids as adipicacid, azelaic acid, suberic acid, sebacic acid, alkenyl succinic acid,fumaric acid, maleic acid, etc., with the alcohols such as butylalcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc), liquid esters ofacid of phosphorus, alkyl benzenes, polyphenols (e.g., biphenols andterphenols), alkyl biphenols ethers, polymers of silicon, e.g.,tetraethyl silicate, tetraisopropyl silicate,tetra(4-methyl-2-tetraethyl) silicate, hexyl(4 methyl-2-pentoxy)disilicone, poly(methyl)siloxane, and polymethylphenyl)siloxane,etc. The base oils may be used individually or in combinations, whenevermiscible or whenever made so by use of mutual solvents.

Preparation of Grease Composition The greases exhibiting superiorproperties of this invention can be prepared by the in situ productionof the mono or polyurea compound followed by the production of thealkaline earth metal carboxylate within the base oil. In thisembodiment, the base oil is charged to the grease kettle along with themonor or polyurea and metal carboxylate precursors, i.e., the reactantswhich combine to form the monor or polyurea compound and metalcarboxylate. In instances where the preferred monor or polyureacompounds are of the type defined by Formula 1, the base oil is chargedwith the desired proportion of diisocyanate, diamine, and monoamine. Inthe preparation of mono or polyurea defined by Formula 2, the base oilis admixed with the desired proportion of diisocyanate, diamine andmonoisocyanate. If the monor or polyurea is of the type defined byFormula 3, then the desired proportion of diisocyanate, diamine,monoisocyanate and monoamine are admixed with the base oil. In instanceswhere the monor or polyurea compound is of the type defined in Formula4, the base oil is charged with the desired proportion of carboxylicacid or anhydride, diisocyanate, diamine, and monoamine ormonoisocyanate. The kettle contents are agitated and the temperature israised to 20 to 160 C. and maintained at that temperature for a periodsufiicient to cause formation of the monor or polyurea compound,generally between about 0.5 and 3 hours.

After the formation of the mono or polyurea compound, the grease kettleis charged with an alkaline earth metal hydroxide or oxide and acarboxylic acid. The ratio of alkaline earth metal hydroxide tocarboxylic acid on an equivalent basis can vary from 1 to 4:1 and ispreferably between 1 and 2:1. The kettle is maintained at a temperaturebetween 70 F. and 150 F. during the process to effect the neutralizationreaction of the alkaline earth metal hydroxide or oxide and carboxylicacid. During the reaction water is released and is preferably removedfrom the system by applying a vacuum on the kettle of 20 to 29 inches ofmercury and heating to about 212 F. and higher.

The grease composition can be further processed by subjecting it toshear hardening. Shear hardening is performed by milling the grease inan extrusion type mill under elevated pressures. This milling improvesthe dispersion of the monor or polyurea and metal carboxylate throughoutthe base oil resulting in a grease of greatly improved consistency. U.S.application Scr. No. 111,517 filed Feb. 1, 1971, and now abandoned,discloses a preferred method of shear hardening a grease which can besuccessfully employed for the composition of this invention.

In addition to the mono polyurea and alkaline earth metal carboxylate,other additives may be successfully employed within the greasecomposition of this invention without affecting its high stability andperformance over a wide temperature scale. One type of additive is anantioxidant or oxidation inhibitor. This type of additive is employed toprevent varnish and sludge formation on metal parts and to inhibitcorrosion of alloyed bearings. Typical antioxidants are organiccompounds containing sulfur, phosphorus or nitrogen, such as organicamines, sulfides, hydroxy sulfides, phenols, etc., alone or incombination with metals like zinc, tin or barium. Particularly usefulgrease antioxidants include phenyl-alpha-naphthyl amine,bis(alkylphenyl)amine, N,N diphenyl-p-phenylenediamine, 2,2,4trimethyldihydroquinoline oligomer, bis(4 isopropylaminophenyl)-ethr,Nacyl-p-aminopheno], N acylphenothiazines, N hydrocarbylamides ofethylenediamine tetraacetic acid, alkylphenol-formaldehyde-aminepolycondensates, etc.

Another additive which may be incorporated into the grease compositionof this invention is an anti-corrodant. The anti-corrodant is employedto suppress attack by acidic bodies and to form protective films overthe metal surfaces which decrease the effect of corrosive materials onexposed metallic parts. A particularly effective corrosion inhibitor isan alkali metal nitrite and preferably so dium nitrite. The combinationof the polyurea thickener and alkaline earth metal carboxylate has beenfound to work exceedingly well within the alkali metal nitrite. Whenthis corrosion inhibitor is employed it is usually used at aconcentration of 0.1 to 5 weight percent and preferably from 0.2 to 2weight percent based on the weight of the final grease composition;

Another type of additive which may be employed herein is a metaldeactivator. This type of additive is employed to prevent or counteractcatalytic effects of metal on oxidation generally by formingcatalytically inactive complexes with soluble or insoluble metal ions.Typical metal deactivators include complex organic nitrogen andsulfur-containing compounds such as certain complex amines and sulfides.An exemplary metal deactivator is mercaptobenzothiazole.

In addition to the above, several other grease additives may be employedin the practice of this invention and include stabilizers, tackinessagents, dropping point improvers, lubricating agents, color correctors,odor control agents, etc.

The following examples are presented to illustrate the practice ofspecific embodiments of this invention and should not be interpreted aslimitations upon the scope of the invention.

EXAMPLE 1 In this example, a diurea thickening agent is prepared and itsproperties tested. A 48 liter stainless steel mixer equipped With astirrer is charged with 3,750 grams of 126 neutral oil and 305 grams oftall oil fatty amine. The contents are agitated at 130 F. for 30 minutesand thereafter 3,750 grams of additional 126 neutral oil with 95 gramsof tolylenediisocyanate are charged to the mixer. The contents areagitated for 40 minutes and recycled through an extrusion type mill at7,500 p.s.i. for an additional 20 minutes.

The milled grease is then heated to 200 F. and 6 grams of ethylenediamine are charged to the mixer to react with any free isocyanategroups. After being milled at 7,500 p.s.i. for 20 minutes, the grease iscooled to F. and admixed with 2,500 grams of 126 neutral oil and 1,708grams of hydrated lime (Ca(OH) Thereafter, 3,900 grams of 126 neutraloil and 1,845 grams of acetic acid are charged to the mixture andagitated for a period of about 80 minutes at a temperature of about 150F.

The mixture is then charged with 200 grams of commercial rust inhibitorand dispersed therein by milling at 7,500 p.s.i. The grease has an ASTMundisturbed penetration (P of 207, and after 60 strokes a workedpenetration (P of 348.

9 EXAMPLE 2 This example is presented to demonstrate the preparation ofa representative tetraurea-calcium acetate composition of thisinvention. A 48 liter stainless steel reaction vessel equipped with astirrer is charged with 7,500 grams of a blend of a parafiinic andnaphthenic oil having a viscosity of 78 SSU at 210 F. hereinafterreferred to as base oil, 880 grams of tall oil fatty amine and 92 gramsof ethylene diamine. The contents of the vessel are stirred for 20minutes at 130 F. and thereafter admixed with 6,000 grams of base oiland 548 grams of tolylenediisocyanate. The vessel is agitated and heldat a temperature of 150 F. for a 30-minute period.

The vessel contents are thereafter milled in an extrusion type mill at apressure of 7,500 p.s.i. and then heated to 200 F. A small sample of thegrease is analyzed and trace amounts of diisocyanate are detected. Anadditional 40 grams of ethylene diamine are charged to the vessel andmixed with the milled grease for a period of minutes at atemperature of210 F. At the end of the 10- minute period, the vessel is cooled to 150F. and 5,000 grams of additional base oil with 2,480 grams of hydratedlime (Ca(OH) are charged to the vessel. The lime and base oil areadmixed with the previously milled grease for 5 minutes at which time anadditional 5,460 grams of base oil and 2,800 of acetic acid are slowlycharged to the vessel over a 25-minute period. The admixture is agitatedfor 30 minutes at 150 F. to assure that the neutralization reactionbetween the calcium hydroxide and acetic acid is complete. Thereafter,320 grams of a commercial rust inhibitor is charged to the vessel andthe contents milled at 7,500 p.s.i. The grease is then admixed with-8,920 grams of base oil and recycled through a mill at a pressure of7,500 p.s.i. The product grease has an undisturbed penetration (P of 232and after 60 strokes a worked penetration (P of 282 (ASTM-217). The ASTMdropping point is 460 F. (ASTMD2265).

A sample of the grease is calculated to have the folwherein T0 is a talloil radical.

1 EXAMPLE 3 This example is presented to demonstrate the effectivenessof a representative grease of this invention containing polyurea and analkaline earth metal carboxylate in long term performance as compared toa typical lithium stearate grease. The polyurea-metal carboxylate greaseto be tested is prepared by the method of Example 2. The lithium greaseis comprised of the following:

Component: Amount, wt. Lubricating oil 1 87 Commercial E.P. agentconcentrate 6 Commercial rust inhibitor 0.3 Lithium hydroxystearate 6 1The lubricating oil is the same type as employed in Example 2 and has aviscosity of 78 SSU at 210 F.

TABLE II.-TIMKEN TEST RESULTS Load Contact pres- Test grease (1bs.) sure(p.s.i.)

Polyurea-metal carboxylate- 50 32, 000 Lithium 45 12, 000

The Timken test reveals the anti-Wear characteristics of the grease witha higher load and higher contact pressure indicating the betteranti-wear properties. It can be seen from the above table that thegrease of the instant invention is superior to the lithium grease inpassing load and far superior in contact pressure.

The two greases are further subjected to a high temperature thin filmtest. The thin film test demonstrates the ability of the grease tolubricate a bearing for a long period of time and is indicative of thebearing life. In the thin film test, the two greases are respectivelyspread in a layer of an inch in thickness on separate strips of steeland exposed in an oven at a temperature of 300 F. The greases areobserved over a period of time and that time when the grease loses itsgrease-like characteristics (becomes hard or turns to lacquer uponcooling) is known as the thin film life.

The aforesaid lithium grease and the grease prepared by the method ofExample 2 are subjected to a thin film test and the results are shown inthe following Table III.

TABLE III [Thin film lives at 300 F.]

Approxi- Condition of mate life grease at room Grease (hrs.) temperatureLithium hydroxy stearate 300 Hard and cracked- Polyurea-metalcarboxylate 1, 000 Grease-like.

It can be seen from the above table that the greases prepared by thepractice of this invention are far superior to the conventional lithiumhydroxy stearate greases in performance. The table demonstrates apredicted 330 percent increase in bearing life.

EXAMPLE 4 TABLE IV.APPAREN T VISCOSITY Viscosity (poises) At 30 F. At 0F. Grease 20 sec.- 200 secr 20 sec: 200 sec.-

Polyureametal carboxylate- 900 330 2, 800 1, 200 Lithium 1, 000 400 4,800 2, 300

As can be seen from the above table, the grease compositions of thisinvention exhibit a viscosity less than viscosity of the lithium greasesat 30 F. and again at 0 F. Particularly significant is the demonstrationthat at 0 F. the viscosity of the composition of this invention is 2,000poise less than the lithium grease composition at 20 sec- 1 1 EXAMPLE 5This example is presented to demonstrate the effectiveness of mono ureasand calcium acetate in making an im- 1 2 eral Test Method 331.1 (NavyHigh Speed Bearing Test). Each of the following greases is expected toexhibit a relatively good dropping point and a satisfactory bearinglife:

TABLE V Mono or polyurea precursors Metal carboxylate precursors Amount,Amount, Composition Type wt. percent Type wt. percent Lube oil typeDPM-4,4 diisoeyanate L--- 4 Barium hydroxide 9. 5 1 p-Phenylene diamincAcetic acid. Octadecylamine p Toluidine 1 2 Hexylisocyanate 2Dianilinemcthanc- 2. 5 Bis(diphenylisocyanate) 1 Tallow amine 2. 9IVIagnesium hydrox e 5.0 3 p-Toluidene 1. 2 Propanoic acid 10. 4 MineralEthylenediamine. 0. 6 Hexanediisocyanate 4. 3 4 Stearic acid 3. 5Calclum hydroxldc 6 Tolylene diisocyanate 2. 2 Acetic acid D p-Phenylenediamlne 0. 7 Hydrocinnamic acid 4. 8 Barium hydroxide Phenylenedlisocyanate 2. 5 Acetic acid Alkylmelhyl Naphthylamine 2. 2 Silicone. 6Maleic anhydride 1. 5 Calcium hydr Deeanediisocyanate-- 2. 4 Aceticacid. Mineral Tall oil fatty amine. 4. 1 7 Tallow amine 3 Tolylened1is0cya nate- 3. 9 Calcium hydroxide Do.

Diethylene triamme 1. l Acetic acid 5 1 Diphenylmethane,4,4-diisoeyanate. 1 Pentaerythntol tetracaproate.

proved grease composition. A one-liter Waring Blender is charged with140 grams of 600 neutral oil and 43.5 grams of tall oil fatty amine atroom temperature. While stirring the contents, 19.9 grams of phenylisocyanate are charged to the blender. The contents are stirred forabout 30 minutes and thereafter allowed to stand overnight.

Calcium hydroxide (11 grams) is charged to the blender and intimatelymixed within the monourea oil mixture. Thereafter 12.4 grams of aceticacid are contacted with the blender contents and stirred until theneutralization reaction ceases. The mixture is dehydrated and admixedwith an additional 50 grams of oil. The grease is then milled and theASTM work penetration is measured. The penetration after 60 strokes (Pis 317. The ASTM Work penetration (P of the mono urea grease without theaddition of the calcium acetate is 336.

This example clearly demonstrates an improvement in work penetration bythe addition of calcium acetate to the grease composition.

EXAMPLE 6 This example is presented to hypothetically demonstrate thepreparation of the various grease compositions of this invent-ion. AZ-gallon grease kettle equipped with cooling jackets and a stirrer ischarged with /2-gallon of a lubricating oil at room temperature. The oilis agitated by the stirrer and selected amounts of the mono or polyureaprecursors, e.g., diisocyanates, monoisocyanates, diamines, carboxylicacids and monoamines, are slowly charged to the kettle. The amines arecharged to the kettle before the addition of the isocyanate anddissolved within the oil. Temperature of the mixture is allowed toincrease to 200 F. and thereafter maintained at that temperature. Afterapproximately 30 minutes, the kettle is charged with an additional/2-gallon of lubricating oil containing selected amounts of an alkalineearth metal hydroxide. The contents of the kettle are recycled through amill at 7,000 p.s.i. to disperse the alkaline earth metal hydroxidethroughout the grease composition. Thereafter, a carboxylic acid ischarged to the kettle and the contents recycled to a mill at 7,500p.s.i. for two hours. During the addition of the alkali metal hydroxideand carboxylic acid, the temperature of the kettle is maintained at 200F.

At the end of the two-hour period, the grease is cooled to ambienttemperature and milled twice to an extrusion type mill at 7,000 p.s.i.The milled grease is then tested according to ASTM-D-2265 (droppingpoint) and Fed- It is apparent that many widely diiierent embodiments ofthis invetion may be made without departing from the scope and spiritthereof.

We claim:

1. A grease composition comprising a major part of a lubricating oilcontaining (1) from 0.5 to weight percent of a mono or polyurea compoundor mixture of mono or polyurea compounds having from 1 to 8 ureidogroups and having a molecular weight between about 375 and 2,500 and (2)from 3 to weight percent of an alkaline earth metal aliphaticmonocarboxylate having from 1 to 3 carbons, wherein the Weight ratio ofalkaline earth metal carboxylate to mono and polyurea compounds is from1 to 15. t I

2. The composition defined in Claim 1, wherein said alkaline earth metalaliphatic monocarboxylate is calcium acetate.

3. The composition defined in Claim 2 wherein said mono or polyureacompound or mixture of mono or polyurea compounds have an average from 3to 4 ureido groups and having molecular weight between about 600 and1,200 and wherein said lubricating oil is a hydrocarbon oil.

4. A grease composition comprising a major portion of an oil oflubricating viscosity, from 3 to 30 weight percent of an alkaline earthmetal aliphatic monocarboxylate having from 1 to 3 carbons and from 0.5to 10 weight percent of a mono or polyurea compound or mixture of monoor polyurea compounds prepared by reacting the following components:

I A diisocyanate having the formula OCN-R-NCO wherein R is ahydrocarbylene having from 2 to 30 carbons; 1 II A polyamine having atotal of 2 to carbons and having the formula:

R0 R0 R0 HI IR1 -I IRzN {N N\ lap/A wherein R and R are the same ordifierent type of hydrocarbylene having from 1 to 30 carbons;

R is hydrogen or a C -C alkyl,

x is an integer from O to 2;

y is an integer from 0 to 1; and

z is an integer equal to 0 when y is l and equal to 1 when y is 0; and

IH A monofunctional compound having from 1 to 30 carbons and selectedfrom the group consisting of monoisocyanate, monoamine and mixturesthereof;

wherein the reaction temperature is from about 60 to 320 F., thereaction time is about 0.5 to 5 hours and the component molar ratios ofI, H and III are 1, -2 and 0.1-2.

5. The composition defined in Claim 4 wherein said diisocyanate istolylene diisocyanate, said polyamine is ethylene diamine and saidmonofunctional compound is a C -C monoamine.

6. The composition defined in Claim 5 wherein the molar ratio ofdiisocyanate to diamine to monoamine is 2:1:2.

7. The composition defined in Claim 6 wherein said monoamine is tall oilfatty amine.

8. The composition defined in Claim 4 wherein said polyamine is atriamine having from 2 to 40 carbons.

9. The composition defined in Claim 8 wherein said triamine isdiethylene triamine.

10. The composition defined in Claim 8 wherein said triamine istert-N-methyl diethylenetriamine.

11. The composition defined in Claim 4 wherein said polyamine ispiperazine.

12. The composition defined in Claim 4 wherein a corrosion inhibitingamount of an alkali metal nitrite is also present.

13. The composition defined in Claim 12 wherein said alkali metalnitrite is sodium nitrite.

14. The composition defined in Claim 4, wherein said alkaline earthmetal aliphatic monocarboxylate is calcium acetate.

15. The composition defined in Claim 1 wherein said alkaline earth metalcarboxylate is a calcium or barium acetate.

16. The composition defined in Claim 14 wherein said oil of lubricatingviscosity is a naphthenic or paraffinic based hydrocarbon lubricatingoil or mixture thereof.

17. The composition defined in Claim 16 wherein said diisocyanate istolylene diisocyanate.

18. The composition defined in Claim 17 wherein said polyamine isethylene diamine and said monofunctional compound is a C -C monoamine,

19. The composition defined in Claim 18 wherein the molar ratio of saiddiisocyanate to said polyamine to said monoamine is about 2:1:2.

References Cited UNITED STATES PATENTS 3,182,020 5/1965 Davis 252-51.5 A3,189,542 6/1965 MorWay et al 252-17 3,278,426 10/1966 Criddle 2525l.5 A3,361,670 l/1968 Hotten 2525l.5 A 3,376,223 4/1968 Criddle 25251.5 A3,243,372 3/1966 Dreher et a1 25251.5 A

25 DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner

1. A GREASE COMPOSITION COMPRISING A MAJOR PART OF A LUBRICATING OILCONTAINING (1) FROM 0.5 TO 10 WEIGHT PERCENT OF A MON OR POLYUREACOMPOUND OR MIXTURE OF MONO OR POLYUREA COMPOUNDS HAVING FROM 1 TO 8UREIDO GROUPS AND HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 375 AND 2,500AND (2) FROM 3 YO 30 WEIGHT PERCENT OF AN ALKALINE EARTH METAL ALIPHATICMONOCARBOXYLATE HAVING FROM 1 TO 3 CARBONS, WHEREIN THE WEIGHT RATIO OFALKALINE EARTH METAL CARBOXYLATE TO MONO AND POLYUREA COMPOUNDS IS FROM1 TO 15.